Unagi 101: Kabayaki, Shirayaki, Fillets, and Sushi Cuts

Unagi can turn a simple bowl of rice into a satisfying meal in minutes. The rich eel, glossy sauce, and lightly charred surface bring a restaurant-style feel without a long ingredient list. Yet labels such as kabayaki, shirayaki, fillet, and sushi cut can make a straightforward purchase seem more complicated than it is.

This guide explains the common styles, which format suits each dish, what to check when buying frozen pre-cooked unagi, and how to reheat it without drying the flesh or burning the sauce.

What Is Unagi?

Unagi is freshwater eel used widely in Japanese cooking. It has soft, rich flesh and enough natural fat to stay succulent when grilled carefully. Most frozen unagi sold for home use is already cleaned, butterflied, cooked, and often seasoned with a sweet savoury sauce. That means the work at home is mainly reheating and assembling the meal.

Unagi is different from anago, which is saltwater conger eel. Anago is generally lighter and more delicate, while unagi is richer and more robust. If you want the familiar glossy eel served over rice, unagi is usually what you are looking for.

Kabayaki vs Shirayaki

Kabayaki is eel grilled with a tare-style sauce, usually built around soy sauce, sweetness, and savoury seasoning. The sauce caramelises on the surface and gives the eel its familiar deep brown glaze. It is the easiest choice for unadon, bento, sushi, or a quick main dish.

Shirayaki is grilled without the dark sweet sauce. Its paler appearance lets the natural flavour of the eel come forward. It is often served more simply, with salt, wasabi, or a light dipping sauce. Shirayaki suits diners who prefer less sweetness or want more control over the final seasoning.

Style or Format	Flavour and Texture	Best Uses	Buying Tip
Kabayaki fillet	Rich, sweet savoury, glazed	Rice bowls, bento, sushi, shared main	Choose an even glaze without heavy burnt patches
Shirayaki fillet	Cleaner eel flavour, less sweet	Simple plates, light sauces, appetisers	Look for moist flesh and gentle, even grilling
Whole butterflied fillet	Soft centre with broad grilled surface	Family rice bowl, slicing to order, table sharing	Best when you want flexible portion sizes
Pre-cut portions	Convenient and evenly sized	Individual rice bowls and lunch boxes	Check that pieces have similar thickness
Sushi slices	Small, neat, ready to assemble	Nigiri, rolls, appetiser platters	Choose when presentation speed matters most

Which Unagi Format Should You Choose?

For an easy rice bowl

Choose a pre-cooked kabayaki fillet. Reheat it, cut it into broad slices, and place it over hot rice. One 200g fillet can make two moderate bowls when served with rice, egg, pickles, soup, or vegetables.

For sushi or a party platter

Pre-cut sushi slices save time, but a whole fillet gives you more control. Chill the reheated eel slightly before cutting so it holds together, then use a sharp knife to make clean pieces for nigiri or rolls.

For less sweetness

Choose shirayaki where available, or use a lightly sauced fillet and avoid adding all the extra sauce from the pack. Pair it with grated daikon, cucumber, spring onion, or wasabi for a fresher balance.

Quality Checks for Frozen Pre-Cooked Unagi

• Packaging: The pack should be sealed and intact, with no leaks or large pockets of air.
• Surface: Look for an even grilled colour. A few darker marks are normal, but large blackened areas may taste bitter.
• Frost: Heavy frost or dry pale edges can indicate moisture loss or temperature changes.
• Shape: A mostly intact fillet is easier to portion and present than one broken into many pieces.
• Product details: Check the pack weight, origin, whether it is pre-cooked, and whether sauce is included.

How to Reheat Unagi Without Drying It Out

Oven or toaster oven

Place the thawed fillet on foil or baking paper, add a small spoonful of water or sauce, and cover loosely for the first part of reheating. Uncover briefly at the end to refresh the glaze. Watch closely because sweet sauce can burn.

Air fryer

Use moderate heat rather than the highest setting. Place the eel on a liner, brush with a little sauce, and heat only until hot. A short final burst can caramelise the surface, but extra minutes will dry the edges.

Pan

Add the fillet to a non-stick pan with a splash of water or sake, cover, and warm gently. Remove the lid near the end and add sauce if needed. This method combines moisture with a lightly glazed finish.

Steam

Steaming gives a soft, moist result and is useful when the fillet looks lean or dry. The surface will be less caramelised, so finish it briefly under a grill if you want more colour.

Simple Ways to Serve Unagi

• Over Japanese rice with shredded egg, cucumber, and spring onion.
• In a sushi roll with avocado or cucumber.
• With soba or udon and a light broth.
• As a shared plate with pickles, salad, and steamed rice.
• In small portions as part of a bento with vegetables and tamagoyaki.

Where to Buy Unagi in Singapore

A pre-cooked frozen fillet gives you the flavour and convenience of unagi without cleaning or grilling eel from scratch. Browse Pan Ocean Singapore's seafood collection for unagi and other convenient seafood for home meals.

Free delivery above $60. Order by 4PM for next-day delivery.